We don't have an out of the box option to add static values. Still as you have guessed you can achieve this with SQL or with a simple method that you can bind to and pass a string with a comma separated values. Check out the following example:
"Split comma separated values to string array."
If you decide to use this approach you may find useful the How to use external assemblies with custom CLR objects in the Report Designer
Have you tried the new visualization options in Telerik Reporting Q2 2013? You can get them from your account.